1. Field of the Invention
The present invention relates to a multi-beam light source device and a multi-beam scanning apparatus using the multi-beam light source device, which simultaneously emit multiple light beams to a photosensitive medium of an electrophotographic copier or printer in order to speedily form an electrostatic latent image on the photosensitive medium. Specifically, the present invention relates to improvements of a multi-beam light source device and a multi-beam scanning apparatus to facilitate the alignment adjusting operations for the optical axes of laser beams emitted by a plurality of laser light sources.
2. Description of the Related Art
As disclosed in Japanese Laid-Open Patent Application Nos.8-68956, 9-197310, 11-23988 and 11-153762, multi-beam light source devices and multi-beam scanning devices are known in which laser beams, emitted by a plurality of laser light sources, are simultaneously applied to a photosensitive medium of an electrophotographic copier or printer in order to form an image on the photosensitive medium or optically write information thereon.
In such multi-beam light source device, disclosed in Japanese Laid-Open Patent Application Nos.11-23988 and 11-153762, the laser light sources are arrayed in the main scanning direction, and a beam synthesizing prism is used to combine diverging laser beams, emitted by the light sources, into collimated laser beams. The conventional multi-beam light source device has a simple configuration and eliminates time-varying changes of the alignment of beam spots on the scanned surface to increase the stability of the performance.
In order to achieve accurate positioning of beam spots on the scanned surface of the photosensitive medium with the conventional multi-beam light source device, it is necessary to increase the accuracy of alignment of the optical axes of the laser beams produced by the beam synthesizing prism, as well as the accuracy of positioning of the beam split surface and the reflection surface of the beam synthesizing prism in the multi-beam light source device. When volume production is required, it is difficult to achieve accurate positioning of beam spots on the scanned surface of the photosensitive medium with the conventional multi-beam light source device. It is difficult to increase the accuracy of alignment of beam spots on the scanned surface in the sub-scanning direction by performing the alignment adjusting operations on the conventional multi-beam light source device.
It is an object of the present invention to provide an improved multi-beam light source device in which the above-described problems are eliminated.
Another object of the present invention is to provide a multi-beam light source device that can easily achieve accurate positioning of the beam spots on the scanned surface by performing the alignment adjusting operations with the multi-beam light source device.
Another object of the present invention is to provide a multi-beam scanning apparatus including a multi-beam light source device that can easily achieve accurate positioning of the beam spots on the scanned surface by performing the alignment adjusting operations with the multi-beam light source device.
Another object of the present invention is to provide a multi-beam scanning apparatus that can achieve stable image reproduction performance even when the multi-beam light source device uses general-purpose light sources.
Another object of the present invention is to provide a multi-beam light source device that can easily achieve accurate positioning of the optical paths of the light beams from the light sources by performing the alignment adjusting operations.
Another object of the present invention is to provide a multi-beam scanning apparatus that can easily achieve accurate positioning of the optical paths of the light beams from the light sources by performing the alignment adjusting operations.
Another object of the present invention is to provide a multi-beam scanning device that can reduce deformations of the light source holder and achieve stable image reproduction performance when performing the alignment adjusting operations with the multi-beam light source device, when fastening the light source holder, or when the ambient temperature fluctuates.
The above-mentioned objects are achieved by a multi-beam light source device comprising: multi-beam light source device comprising: a light source unit holding light sources and coupling lenses, the coupling lenses coupling light beams emitted by the light sources; a base member holding the light source unit such that the light beams from the light source unit held by the base member are rotatable in a direction perpendicular to a main scanning direction of an optical scanning device; and an angle adjustment mechanism provided for adjusting a mounting angle of the light source unit relative to the base member, so that respective pitches of beam spots, formed on a scanned surface by the light beams, in the direction perpendicular to the main scanning direction are variable in accordance with the mounting angle adjustment.
The above-mentioned objects are achieved by a multi-beam scanning apparatus including a multi-beam light source device, the multi-beam light source device comprising: a light source unit supporting light sources and coupling lenses to array the light sources in the main scanning direction, the coupling lenses coupling light beams emitted by the light sources; and an optical path changing unit changing an optical path of part of the light beams of the light source unit such that the light beams from the light source unit and the light beams from the optical path changing unit are converted into adjacent light beams that intersect each other in the main scanning direction in the vicinity of a deflector of the optical scanning unit, the optical path changing unit being provided to vary an intersecting angle of the adjacent light beams.
The above-mentioned objects are achieved by a multi-beam light source device comprising: a light source holder holding a plurality of light sources, the light sources emitting multiple light beams; a fastening member supporting the light source holder to maintain a direction of the light source holder relative to an emission axis of the light beams, the fastening member having fastening portions secured to a base member that is fixed to a focusing optical device, wherein the light source holder and the fastening member form a light source unit; and a mounting member supporting the light source unit on the base member by exerting a pressing force on the light source unit against the base member so as to match a direction of the light source unit relative to the base member with an emission axis perpendicular to a scanned surface of an optical scanning unit.
The above-mentioned objects are achieved by a multi-beam light source device comprising: a light source holder holding a plurality of light sources, the light sources emitting multiple light beams; and a fastening member supporting the light source holder to maintain a direction of the light source holder relative to an emission axis of the light beams, the fastening member having fastening portions secured to a base member that is fixed to a focusing optical device, wherein the light source holder is separately provided with and attached to the fastening member to form an integral light source unit, and the light source holder and the fastening member are of different materials.
The above-mentioned objects are achieved by a multi-beam light source device for use in a multi-beam scanning apparatus, the multi-beam light source device comprising: a plurality of first light sources; a plurality of first coupling lenses which couple light beams emitted by the first light sources; a first light source holder which holds the first light sources and the first coupling lenses; a plurality of second light sources; a plurality of second coupling lenses which couples light beams emitted by the second light sources; a second light source holder which holds the second light sources and the second coupling lenses; a base member which integrally supports the first light source holder and the second light source holder by applying pressure of an elastic member thereto to maintain a direction of each light source holder relative to an emission axis of the light beams; an attitude adjustment mechanism which is provided for adjusting an optical path direction of the light beams of one of the first and second light sources relative to the emission axis by moving one of the first and second light source holders to the other light source holder against the pressure of the elastic member.
The above-mentioned objects are achieved by a multi-beam scanning apparatus including an optical scanning unit and a multi-beam light source device, the multi-beam light source device comprising: a plurality of first light sources; a plurality of first coupling lenses which couples light beams emitted by the first light sources; a first light source holder which holds the first light sources and the first coupling lenses; a plurality of second light sources; a plurality of second coupling lenses which couples light beams emitted by the second light sources; a second light source holder which holds the second light sources and the second coupling lenses; a base member which integrally supports the first light source holder and the second light source holder by applying pressure of an elastic member thereto to maintain a direction of each light source holder relative to an emission axis of the light beams; and an attitude adjustment mechanism which is provided for adjusting an optical path direction of the light beams of one of the first and second light sources relative to the emission axis by moving one of the first and second light source holders to the other light source holder against the pressure of the elastic member, wherein the optical scanning unit scans a surface of a photosensitive medium in a main scanning direction by focusing the multiple light beams of the multi-beam light source device onto the scanned surface.
The above-mentioned objects are achieved by a multi-beam light source device comprising: a light source holder which holds a plurality of light sources, the light sources emitting multiple light beams; a fastening member which supports the light source holder to maintain a direction of the light source holder relative to an emission axis of the light beams, the fastening member having fastening portions secured to a base member that is fixed to a housing, wherein the light source holder is separately provided with and attached to the fastening member to form an integral light source unit; and a mounting mechanism which is provided for adjusting a mounting angle of the light source unit relative to the base member, so that respective pitches of beam spots, formed on a scanned surface by the light beams, are variable in a sub-scanning direction in accordance with the mounting angle adjustment.
The above-mentioned objects are achieved by a multi-beam light source device comprising: a light source holder which holds light sources and coupling lenses, the coupling lenses coupling multiple light beams emitted by the light sources, the light source holder having a first linear expansion coefficient; a fastening member which supports the light source holder to maintain a mounting angle of the light source holder relative to an emission axis of the light beams, the fastening member having a second linear expansion coefficient, and the fastening member having fastening portions secured to a base member fixed to a housing; and an intermediate member which is provided between an outside peripheral surface of the light source holder and an inside peripheral surface of the fastening member such that the light source holder is supported onto the fastening member through the intermediate member without contacting the fastening member directly.
The above-mentioned objects are achieved by an image forming system including a multi-beam light source device and a multi-beam scanning apparatus, the multi-beam light source device comprising: a light source unit holding light sources and coupling lenses, the coupling lenses coupling light beams emitted by the light sources; a base member holding the light source unit such that the light beams from the light source unit held by the base member are rotatable in a direction perpendicular to a main scanning direction of an optical scanning device; and an angle adjustment mechanism provided for adjusting a mounting angle of the light source unit relative to the base member, so that respective pitches of beam spots, formed on a scanned surface by the light beams, in the direction perpendicular to the main scanning direction are variable in accordance with the mounting angle adjustment.
The above-mentioned objects are achieved by an image forming system including a multi-beam light source device and a multi-beam scanning apparatus, the multi-beam light source device comprising: a light source unit supporting light sources and coupling lenses to array the light sources in the main scanning direction, the coupling lenses coupling light beams emitted by the light sources; and an optical path changing unit changing an optical path of part of the light beams of the light source unit such that the light beams from the light source unit and the light beams from the optical path changing unit are converted into adjacent light beams that intersect each other in the main scanning direction in the vicinity of a deflector of the optical scanning unit, the optical path changing unit being provided to vary an intersecting angle of the adjacent light beams.
The above-mentioned objects are achieved by an image forming system including a multi-beam light source device and a multi-beam scanning apparatus, the multi-beam light source device comprising: a light source holder holding a plurality of light sources, the light sources emitting multiple light beams; a fastening member supporting the light source holder to maintain a direction of the light source holder relative to an emission axis of the light beams, the fastening member having fastening portions secured to a base member that is fixed to a focusing optical device, wherein the light source holder and the fastening member form a light source unit; and a mounting member supporting the light source unit on the base member by exerting a pressing force on the light source unit against the base member so as to match a direction of the light source unit relative to the base member with an emission axis perpendicular to a scanned surface of an optical scanning unit.
The above-mentioned objects are achieved by an image forming system including a multi-beam light source device and a multi-beam scanning apparatus, the multi-beam light source device comprising: a light source holder holding a plurality of light sources, the light sources emitting multiple light beams; a fastening member supporting the light source holder to maintain a direction of the light source holder relative to an emission axis of the light beams, the fastening member having fastening portions secured to a base member that is fixed to a focusing optical device, wherein the light source holder is separately provided with and attached to the fastening member to form an integral light source unit, and the light source holder and the fastening member are of different materials.
In the multi-beam light source device and the multi-beam scanning apparatus of one preferred embodiment of the invention, the angle adjustment mechanism is provided for adjusting a mounting angle of at least one of the first and second light source units relative to the base member, so that respective pitches of beam spots, formed on the scanned surface by the light beams from the first and second light source units, are variable in the sub-scanning direction in accordance with the mounting angle adjustment. The multi-beam light source device of the present invention is effective in providing accurate positioning of the beam spots on the scanned surface by performing the alignment adjusting operations.
In the multi-beam scanning apparatus of one preferred embodiment of the invention, the multi-beam scanning device is provided with the angle adjustment mechanism. The multi-beam scanning apparatus of the present invention is effective in providing accurate positioning of the beam spots on the scanned surface by performing the alignment adjusting operations.
The multi-beam scanning apparatus of one preferred embodiment of the invention is effective in providing stable image reproduction performance even when the multi-beam light source device uses general-purpose light sources.
The multi-beam light source device and the multi-beam scanning apparatus of one preferred embodiment of the invention are effective in easily providing accurate positioning of the optical paths of the light beams from the light sources by performing the alignment adjusting operations.
The multi-beam scanning apparatus and the multi-beam light source device of one preferred embodiment of the invention are effective in reducing deformations of the light source holder and providing stable image reproduction performance.